Localizing sound to a predefined area is desirable in many situations, including playing video games, participating in teleconferences, giving presentations at trade shows, delivering narration for art exhibits, and many more analogous circumstances. Is some cases, it is practical to localize using walls (such as the walls of a conference room). In other situations, it may be practical to localize sound through the use of headphones or ear buds (such as are used for many systems that provide narration for art exhibits in museums), yet there are other situations (such as at trade shows) where walls are not an option for localizing sound. Additionally, there are situations where the level of sound isolation desired may not be achievable by walls alone. Applications such as video games may present further challenges where it is desirable not only to isolate sound from nearby areas (for instance areas where people may be sleeping), but where it is also desirable to provide directional cues so that certain sounds seem to come from a given direction, independent of the direction that a player's head may be turned.
The playing of video games is one of the most popular recreational activities in the world, with annual revenues exceeding 78.5 billion dollars in 2012. Video games are sometimes played by lone individuals and sometimes played by groups of individuals. When video games are played by a group of individuals, sometimes individuals are remote from each other and the game is played over a network, and sometimes the group of individuals are physically in the same room. A third possibility is that a group of individuals in the same room may be playing a video game over a network with other individuals or groups at remote locations.
One feature of many modern video games which is important to many gamers is the game's ability to create sounds which appear to come from or actually do come from different directions. One way this is done on many popular video games is to design the game's audio to be played through a “5.1” speaker system. Such speaker system has a front center audio driver, a front left audio driver, a front right audio driver, a rear left audio driver, a rear right audio driver, and a sub-woofer.
Sub-woofers known in the art are often one or more vibratile diaphragms coupled to room air on one side and to a sealed or ported enclosure on the other side. Alternately some sub-woofers known in the art are constructed as two acoustic transmission lines acoustically coupled to opposite sides of a vibratile diaphragm, as disclosed in U.S. Pat. No. 4,628,528 (Bose, et al., hereinafter Bose), which is herein incorporated by reference. The sub-woofer produces low-frequency sounds (for which directionality cannot be distinguished), so it may be placed anywhere in a room. The other drivers are positioned as described above so that the direction of origin of sounds which emanate from those speakers can be part of the virtual reality experience for a person playing the game.
It is common for one member of a household to be an avid video game player, while other members of the household may not be. As such, it is not uncommon within a household for a person playing a video game to want to have the sound of that video game turned up loud enough that people elsewhere in the house may find the sound distracting or disturbing. Low-frequency sound in particular travels relatively unimpeded through a home compared to higher frequency sounds.
While headphones or ear buds (both herein referred to as headphones) can partly address isolating sound that a person playing a video game hears, headphones have two disadvantages when it comes to realism of sound. First, although directionality can be experienced through headphones if the sound signals fed to the headphones are properly pre-processed through binaural processing, low-frequency sound is partly experienced through the body and partly experienced through the ears, so if the low-frequency sounds of a video game are played only through earphones, the body sensations of those low-frequency sounds will be lacking for the user. The second disadvantage of using headphones to experience sound directionality is that if one turns one's head, the direction the sound appears to be coming from changes, while if sound source direction comes from a speaker system (such as the “5.1” speaker system described above) which does not move when one turns one's head then a more realistic virtual reality is experienced by the user.
There is a need for an innovative video game sound system which can produce head-orientation-independent directionality and body-experienced low frequencies, while providing less sound propagation to nearby rooms than is possible with standard 5.1 sound systems.
While the above need may be partly met by simply moving the drivers of a standard 5.1 audio system close to the user, such a solution is inconvenient, and such a solution is not useful if a group of people are playing the video game together in the same room. As such, there is also a need for a realistic video sound system which will allow a group of people to play a video game together in the same room, each experiencing a high-quality audio virtual reality, while at the same time propagating less sound to nearby rooms than is possible with sound systems known in the art.
Trade show displays, in-store displays, and museum displays are further examples of applications where a localized audio experience is desired. In such situations, a person may be walking by an object of potential interest, and persons offering that object for sale or use or display may wish to provide an audio experience to augment the viewer's experience of the object or display. Such an audio experience might include a narrative, music, sound effects, or some combination of such audio. Some museums provide such audio through audio headsets worn by users and driven by battery-powered audio systems triggered by entering a code that goes with the object being viewed. U.S. Pat. No. 5,532,438 to Brown (hereinafter Brown) discloses a sound localization system employing a dome-shaped acoustic reflecting element to focus stereo sound to a users ears when the user's head is positioned in a predetermined place and orientation. There is a need for innovative technologies which provide localized sound such as might be used to accompany an object or display, without the need for headphones, in a way that provides the possibility for multiple persons standing within an area to hear approximately the same audio, and in a way that localizes bass as well as higher frequency sounds.